Battle of Mons Graupius

The Battle of Mons Graupius was fought in 84 AD near present-day Inverness, Scotland during the Roman conquest of Britain. Encountering the Caledonian army, the Roman commander Agricola initially employed his auxiliaries. The Caledonian chariots were dispersed by the Roman cavalry, which then fell on the enemy rear. The battle temporarily crushed Scottish resistance to Roman expansion in the British Isles, but, just a few years later, Emperor Domitian withdrew almost all Roman forces from Scotland and redeployed them to the Dacian front.

Background
Following the 60 AD Battle of Watling Street, the last major Brythonic resistance to the Roman Empire was crushed, and the Romans proceeded to create a new province in Britannia. The Romans considered the whole of Britannia to belong to them, however, and, in 83 AD, Gnaeus Julius Agricola sent a Roman fleet north to Scotland to intimidate the Caledones, the most powerful Celtic tribe in the north. The 25,000-strong Roman and auxiliary army was outnumbered by the 30,000-strong Celtic army; the Caledones were the last unconquered British tribe, and they prepared to stage a last stand against the rapidly expanding Romans. However, the Romans forced the Caledones' hand. The Romans moved on the Caledonian granaries just after harvest season in 84 AD, threatening the Caledones with starvation the following winter if they did not intercede. Ultimately, the two forces met in battle at Mons Graupius near present-day Inverness in northern Scotland.

Battle
8,000 Celtic auxiliaries formed the center of the Roman line, flanked on both sides by cavalry and reinforced by a reserve of Roman legionaries. The Caledones held the hillside of Mons Graupius, and their chariots were deployed on the level ground at the foot of the hill. After an exchange of javelins, Agricola sent forth his Belgic auxiliaries, who cut down the Caledonians at the base of the hill. Agricola then sent his cavalry to outmaneuver the Caledonian army, routing its chariots, outflanking the Celtic warriors, and attacking them from the rear. The Caledonians were routed and ruthlessly pursued as they attempted to flee to nearby woodland; not one Roman unit participated in the battle, which was won entirely by Rome's auxiliaries.

Aftermath
Shortly after the battle, Emperor Domitian - who had originally sought to continue the campaign - was forced to redeploy the Roman forces in Scotland to the Balkans to subdue the rebellious Dacians. Agricola was forced to cede most of his recent conquests, including his fort at Inchtuthill, and, during the reign of Trajan in the early 2nd century AD, the remaining Roman garrisons in southern Scotland were ousted by a Celtic rebellion and forced to retreat to what would become the Hadrian's Wall border in 120 AD.